In deployment of the Government Agreement 2025-2029, the Law of 11 December 2025 on Miscellaneous Provisions brings important changes to the Belgian expat regime (see our previous post on this topic). Although, at first sight, this new tax legislation is ‘as such’ considerably improving the Belgian special tax regime for incoming taxpayers and researchers, there are a number of practical questions and uncertainties as to the implementation of these changes (should companies choose to apply these), especially considering the tax law has “retroactive effect”. On 22 December 2025, the Belgian social security authorities (NSSO) published their viewpoint on the amended tax legislation, via a first update of their administrative instructions. The result is not entirely in line with the expectation of many employers in Belgium.
Making the expat regime more attractive again
The changes under the new legislation include:
It is important to note that these changes will apply retroactively as from income year 2025. In anticipation of the publication of the final text of law, timing wise, this triggers of course various practical considerations, as the year is closing and most 2025 year-end payroll calculations have been made. Moreover, in many cases, the implementation of the new rules will also have an impact on the underlying contracts/assignment letters and subsequent annexes.
Incoming taxpayers who started working in Belgium between 1 January 2025 and the 10th day following the (upcoming) publication of the new legislation in the Belgian Official Gazette, and who met all conditions for the expat regime except for the minimum annual gross salary threshold of EUR 75.000, will exceptionally still be able to submit an application towards the Belgian tax authorities for the application of the expat regime (assuming they meet the adjusted minimum annual gross salary of EUR 70.000). They will only be able to do so within a 3-month window, as from the 10th day after the publication of the text of law in the Belgian Official Gazette.
One of the outstanding points for the implementation of the changes was the anticipated viewpoint of the Belgian social security authorities. Would they agree with the non-application (i.e. exemption) of Belgian employer and employee social security contributions on the increased tax-free allowance for recurring costs proper to the employer (i.e. maximum 35% on top of the gross annual remuneration and without the absolute ceiling of EUR 90.000)? As the Belgian social security authorities previously aligned their position with the Program Law of 27 December 2021 introducing the new expat regime, one would perhaps expect that the same social security authorities would now also adopt the most recent update of tax law in this respect.
Unfortunately, this is not the case. On 22 December 2025, the Belgian social security authorities announced (in a very concise manner) that the Royal Decree of 28 November 1969 is not changed. This implies that they will continue to apply the tax rules as they were introduced on 1 January 2022. Only on the 75K minimum gross remuneration threshold one could debate whether keeping the legal text as it is, also means that the ‘old’ threshold remains. However, the main issue remains that the NSSO is thus (almost) completely ignoring the new tax legislation of 11 December 2025.
How to proceed
When revisiting the 2025 payrolls, this means that for tax purposes up to 35% of the recurring costs can be (retroactively) considered tax-free, whereas for social security purposes the 30% (and EUR 90K ceiling must still be respected). In situations where the Belgian social security regime for employees is applicable, this would in first instance mean that if a company pays recurring expenses of 35% on top of the qualifying gross remuneration, 5% (out of the 35%) would become subject to employer and employee social security contributions. This obvious misalignment between the social security authorities (narrow application) and the amended tax legislation (broader application) will “overcomplicate” many calculations and payrolls in a manner that reaches far beyond normal proportions. It undermines a swift implementation of the new tax rules and will most likely trigger difficult discussions.
One can only hope that legal texts are amended so that the Belgian social security authorities have a legal basis to align with the tax authorities. The coming weeks should result in more clarity on this topic. Stay tuned for more detailed information. We will continue to further monitor this and keep you informed on any further developments.
For a deeper discussion on the above, please reach out to your Vialto Partners point of contact, or alternatively:
Philip Maertens
Partner
Nic Boydens
Partner
Bart Elias
Partner
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